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.TH TTY 1 "Aug 11, 2009"
.SH NAME
tty \- return user's terminal name
.SH SYNOPSIS
.LP
.nf
\fB/usr/bin/tty\fR [\fB-l\fR] [\fB-s\fR]
.fi

.SS "ksh93"
.LP
.nf
\fBtty\fR [ \fIoptions\fR ]
.fi

.SH DESCRIPTION
.SS "/usr/bin/tty"
.sp
.LP
The \fBtty\fR utility writes to the standard output the name of the terminal
that is open as standard input. The name that is used is equivalent to the
string that would be returned by the \fBttyname\fR(3C) function.
.SS "ksh93"
.sp
.LP
The \fBksh93\fR \fBtty\fR built-in writes the name of the terminal that is
connected to standard input onto standard output. If the standard input is not
a terminal, "not a tty" will be written to standard output.
.SH OPTIONS
.sp
.LP
The following options are supported:
.SS "/usr/bin/tty"
.sp
.ne 2
.na
\fB\fB-l\fR\fR
.ad
.RS 6n
Prints the synchronous line number to which the user's terminal is connected,
if it is on an active synchronous line.
.RE

.sp
.ne 2
.na
\fB\fB-s\fR\fR
.ad
.RS 6n
Inhibits printing of the terminal path name, allowing one to test just the exit
status.
.RE

.SS "ksh93"
.sp
.ne 2
.na
\fB\fB-l\fR\fR
.ad
.br
.na
\fB\fB--line-number\fR\fR
.ad
.RS 18n
Write the synchronous line number of the terminal on a separate line following
the terminal name line.  If the standard input is not a synchronous terminal
then "not on an active synchronous line" is written.
.RE

.sp
.ne 2
.na
\fB\fB-s\fR\fR
.ad
.br
.na
\fB\fB--silent\fR|\fBquiet\fR\fR
.ad
.RS 18n
Disable the terminal name line. Portable applications should use [[ -t 0 ]]
instead.
.RE

.SH ENVIRONMENT VARIABLES
.sp
.LP
See \fBenviron\fR(7) for descriptions of the following environment variables
that affect the execution of  \fBtty\fR: \fBLANG\fR, \fBLC_ALL\fR,
\fBLC_CTYPE\fR,  \fBLC_MESSAGES\fR,  and \fBNLSPATH\fR.
.SH EXIT STATUS
.sp
.LP
The following exit values are returned:
.sp
.ne 2
.na
\fB\fB0\fR\fR
.ad
.RS 6n
Standard input is a terminal.
.RE

.sp
.ne 2
.na
\fB\fB1\fR\fR
.ad
.RS 6n
Standard input is not a terminal.
.RE

.sp
.ne 2
.na
\fB\fB>1\fR\fR
.ad
.RS 6n
An error occurred.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
CSI	Enabled
_
Interface Stability	Committed
_
Standard	\fBstandards\fR(7).
.TE

.SH SEE ALSO
.sp
.LP
.BR isatty (3C),
.BR ttyname (3C),
.BR attributes (7),
.BR environ (7),
.BR standards (7)
.SH DIAGNOSTICS
.sp
.ne 2
.na
\fB\fBnot on an active synchronous line\fR\fR
.ad
.sp .6
.RS 4n
The standard input is not a synchronous terminal and \fB-l\fR is specified.
.RE

.sp
.ne 2
.na
\fB\fBnot a tty\fR\fR
.ad
.sp .6
.RS 4n
The standard input is not a terminal and \fB-s\fR is not specified.
.RE

.SH NOTES
.sp
.LP
The \fB-s\fR option is useful only if the exit status is wanted. It does not
rely on the ability to form a valid path name. Portable applications should use
\fBtest\fR \fB-t\fR.
